Conduit end fittings have been used for many years to anchor the conduit member of a coaxial control cable assembly to a support member. Early devices typically exhibited certain operational or assembly problems. One example of an early prior art device is the assembly disclosed in the Bratz U.S. Pat. No. 2,869,905. The fitting described therein was fabricated from a single blank of metal stock. To provide the fitting with a sufficient conduit compression load resistance, the struck-out portions or tabs had to be relatively thick, and consequently, the metal stock material from which the tabs were formed had to have a relatively large thickness dimension. As a consequence, the resilient prongs of the fitting, which were fabricated from the same metal stock material, were also thick and the flexibility of the prong members was limited. Because of the limited flexibility of the prong members it was difficult to depress the prong members without utilizing special installation tools.
To overcome the disadvantages of the Bratz device, a multi-component conduit anchorage device or fitting was employed so that the required thickness of the tab members did not dictate the thickness of the prong members. One early device of this type is described in U.S. Pat. No. 3,366,405 to Sevrence. The depressible prongs of this device are integrally fabricated from a relatively thin tubular spring clip or anchor member, however, the remaining structure of the clip or anchor member and the corresponding interrelated structure of the main body member of the fitting with which the clip or anchor member operatively cooperates is relatively complex, which renders such fittings expensive to manufacture. Consequently, such devices are not economically practical.
Still other prior art cable anchoring assemblies are exemplified by the assemblies disclosed in U.S. Pat. No. 3,415,549 to Chatham and U.S. Pat. No. 3,221,572 to Swick. While these assemblies are also of the multi-component type, such assemblies, like those of Sevrence and Bratz, are relatively expensive to manufacture, and the installation operation is relatively difficult to perform and quite time-consuming to accomplish. This is due to the fact that in assembling the fittings of Chatham and Swick, various auxiliary operations must be performed upon the various components of the fittings, such as, for example, swaging, beading, welding, or the like.
Of course, other forms of clamps are known in other fields. For example, U.S. Pat. No. 2,514,504 to Moline discloses a pipe clamp that includes an inner flanged sleeve and an outer sleeve that includes tapered fingers. The connection is said to be sufficiently secure that train vibrations and sudden impact will not adversely affect the connection. While this connection might have been acceptable for pipes, the connection is not readily adaptable to control cable end fittings. To begin with, the clamp is specifically designed to permit slight pipe displacement with respect to the mounting plate. To this end, the first cylindrical member is movable longitudinally along the pipe. In addition, the first cylindrical member includes at least two longitudinal slots that allow the diameter of the cylindrical member to be reduced under pressure. Moreover, the Moline clamp relies on driving one element to force the two cylindrical members together and reduction of the diameter of the inner member to effect retention of the rings in the assembled position.
Other assemblies are described in U.S. Pat. No. 2,559,759 issued to DeSwart; U.S. Pat. No. 4,626,620 issued to Plyler; U.S. Pat. No. 4,981,310 issued to Belisaire; U.S. Pat. No. 2,424,757 issued to Klumpp and U.S. Pat. No. 3,427,894 issued to Tschanz. None of the designs disclosed in these patents is directly applicable to cable control end fittings and consequently none of these designs satisfy the special needs of such end fittings. Among other things, the designs do not contemplate capping the end of a conduit with zero lash, while still permitting the inner core to pass through the support wall.
U.S. Pat. No. 4,131,379 to Gordy addressed some of these problems by providing a three-piece self-retaining cable anchoring assembly that is quickly and easily mounted within an opening contained in a support member without the use of special installation tools. The device described by Gordy includes an inner sleeve member, an outer sleeve member concentrically arranged about the inner sleeve member, and a collar member concentrically arranged about the outer sleeve member. One end of the collar member abuts one side of the support, the other end of the collar member is supported against axial displacement by flange portions at the corresponding ends of the inner and outer sleeve members. The outer sleeve member includes a plurality of circumferentially arranged external resilient prongs that engage the other side of the support, which outer sleeve member is connected against axial displacement relative to the inner sleeve and collar members. Consequently, the collar flange and the outer sleeve prongs grip opposite surfaces of the support structure to rigidly connect the anchoring device thereto.
There remains, however, several disadvantages with current "spring clip" brake cable end fittings based on Gordy's original disclosure. To begin with, the tabs must be compressed during installation to the mating part since the spring tabs are expanded prior to installation. This requires a significant installation force.
In addition, there is no way to adjust a clip for different thicknesses of the mating parts. As a result, different parts must be used for different applications.
U.S. Pat. No. 5,653,147 to Kelley et al. addressed some of the problems from Gordy by providing for mounting of a two-piece flexible tubular conduit and a flexible core element using a retainer and collar assembly having cantilever legs attached to the conduit. This device is easily installed by pressing the collar assembly into a precut hole in a wall or bracket such that cantilever legs wedge outwardly against the hole and are retained by surfaces on the collar. The collar assembly and cantilever legs do not require compression during installation in the hole because legs expand over the collar assembly as the assembly is compressibly installed in the hole.
However, the design of Gordy does not address significant problems with the wide variety of installation surfaces that may call for use of a retaining device. These problems can include widely varying thicknesses of walls, for which the Kelley et al. device has a limited range of applicability, and problems with slippage of the Kelley et al. assembly after installation in a retaining wall or bracket. In addition, Kelley et al. describes only a two-piece assembly. The two-piece assembly presents additional difficulties since the cantilever legs assembly can become separated from the collar assembly. Further, a two-piece assembly requires two separate moldings or other fabrication processes, one for each piece.
Thus, there remains a need for an anchoring assembly that is inexpensive, easy to install and adaptable to support walls of significantly different thickness, while assuring minimal slippage or other movement of the installed device. It is the principal object of the present invention to provide an anchoring assembly that meets these needs. It is a further object of the present invention to provide various anchoring assembly embodiments that are particularly useful in the context of end fittings used in cable anchoring assemblies. It is a further object of the present invention to provide a device constructed of a single, frangible piece, facilitating assembly and fabrication.